JP2022511928A - SOH correction method and device, battery management system, and storage medium - Google Patents

Abstract

A SOH correction method and device, a battery management system, and a storage medium, wherein the method is between the ratio of the cumulative charge / discharge capacity change amount of the battery core to the corresponding voltage parameter change amount and the voltage parameter itself. The step (101) for acquiring the relationship graph, the step (102) for determining the effective peak point in the relationship graph, the step (103) for determining the SOH reference value corresponding to the voltage parameter data at the effective peak point, and the SOH. A step (104) of correcting the current SOH based on the reference value is included. This method can improve the estimation accuracy of SOH. [Selection diagram] Fig. 1

Description

This application claims the priority of Chinese Patent Application No. 201910413430.9, entitled "SOH Correction Methods and Devices, Battery Management Systems, and Storage Mediums," filed May 17, 2019, and all of the applications. The content of is incorporated in the text.

The present application relates to the field of battery technology, and more particularly to SOH correction methods and devices, battery management systems, and storage media.

Since a battery inevitably ages or deteriorates in long-term use and the battery capacity is significantly reduced, it is necessary to estimate the SOH (State of Health) of the battery.

In the prior art, the detection method for SOH of the battery is as follows. After acquiring the open circuit voltage OCV of the battery core when all vehicles are stationary or in a small current state and acquiring the charge state SOC based on the search table of the pre-defined OCV-SOC relationship graph, the cumulative total of the SOC calculation period. The actual capacity of the battery core is estimated from the charge capacity, and the SOH is further estimated.

However, when the OCV-SOC relation graph changes with aging, the calculation error of the charge state (SOC) increases and the estimated SOH is unreliable. In this case, when charging with the same charging current, the actual magnification is also large. Therefore, there are problems such as overcurrent risk.

The present application provides SOH correction methods and devices, battery management systems, and storage media that can solve the inaccurate problem of SOH estimation due to the deviation of the OCV-SOC relation graph after aging and improve the estimation accuracy of SOH. The purpose is to provide.

According to the first aspect, the embodiments of the present application provide a SOH correction method, wherein the correction method is described.
The step of acquiring the relationship graph between the ratio of the cumulative charge / discharge capacity change amount of the battery core to the corresponding voltage parameter change amount and the voltage parameter itself,
Steps to determine the effective peak point in the relationship graph,
A step of determining the SOH control value corresponding to the voltage parameter data at the effective peak point based on the correspondence between the peak voltage parameter data defined in advance and the SOH control value.
Includes a step of correcting the current SOH based on the SOH reference value.

According to the second aspect, the embodiments of the present application provide a SOH correction device, which is a device.
A relationship graph acquisition module that acquires a relationship graph between the ratio of the cumulative charge / discharge capacity change amount of the battery core to the corresponding voltage parameter change amount and the voltage parameter itself.
The effective peak point determination module that determines the effective peak point in the relationship graph,
An SOH control value determination module that determines the SOH control value corresponding to the voltage parameter data at the effective peak point based on the correspondence between the peak voltage parameter data defined in advance and the SOH control value.
Includes an SOH correction module that corrects the current SOH based on the SOH reference value.

According to the third aspect, the embodiment of the present application provides a battery management system including the above-mentioned SOH correction device.

According to the fourth aspect, the embodiment of the present application is a computer-readable storage medium in which the program is stored, and the computer reading in which the above-mentioned SOH correction method is realized when the program is executed by the processor. Provide a possible storage medium.

As described above, the embodiment of the present application is preliminarily defined by quantifying the change rule of such an OCV-related graph for a phenomenon in which the OCV-related graph changes significantly after the battery core of some systems ages. Since the correspondence between the peak voltage parameter data and the SOH reference value is shown, if it is necessary to correct the SOH for the problem that the SOH estimation is inaccurate due to the deviation of the OCV-SOC relationship graph after aging, the battery Obtain a relational graph of the ratio of the cumulative charge / discharge capacity change of the core to the corresponding voltage parameter change and the voltage parameter itself to determine the effective peak point in the relational graph, and then the pre-defined peak. It is possible to correct the current SOH based on the SOH standard value simply by determining the SOH standard value corresponding to the voltage parameter data at the effective peak point based on the correspondence between the voltage parameter data and the SOH standard value. Therefore, the estimation accuracy of SOH can be improved.

Hereinafter, with reference to the drawings, the features, advantages and technical effects of the exemplary embodiments of the present application will be described in detail. The drawings are not drawn at a substantial scale.

It is a flowchart of the SOH correction method which concerns on 1st Embodiment of this application. It is a schematic diagram of the dQ / dOCV-OCV relational graph which concerns on embodiment of this application. It is a graph which shows the change with aging of dQ / dOCV-OCV which concerns on embodiment of this application. It is a flowchart of the SOH correction method which concerns on the 2nd Embodiment of this application. It is a flowchart of the SOH correction method which concerns on 3rd Embodiment of this application. It is a flowchart of the SOH correction method which concerns on 4th Embodiment of this application. It is a flowchart of the SOH correction method which concerns on 5th Embodiment of this application. It is a flowchart of the SOH correction method which concerns on 6th Embodiment of this application. It is a flowchart of the SOH correction method which concerns on 7th Embodiment of this application. It is a block diagram of the SOH correction apparatus which concerns on embodiment of this application.

Hereinafter, features and exemplary embodiments of various aspects of the present application will be described in detail. In the detailed description below, many specific details are presented to provide a complete understanding of the present application.

The embodiments of the present application provide SOH correction methods and devices, battery management systems, and storage media, and the embodiments of the present application are based on the phenomenon that the OCV-related graph changes significantly after the battery core of some systems ages. By quantifying the change rule of the OCV-related graph and estimating the aging SOH, the estimation accuracy of the SOH is improved, and the inaccurate problem of the SOH estimation due to the deviation of the OCV-SOC-related graph after aging is solved. Can be resolved.

FIG. 1 is a flowchart of the SOH correction method according to the first embodiment of the present application, and as shown in FIG. 1, the SOH correction method includes steps 101 to 104.

In step 101, the relationship graph between the ratio of the cumulative charge / discharge capacity change amount of the battery core to the corresponding voltage parameter change amount and the voltage parameter itself is acquired.

Here, the voltage parameter includes the open circuit voltage OCV of the battery core or the detection voltage during charging / discharging of the battery core. The amount of change in the cumulative charge / discharge capacity indicates the amount of change in the amount of electric power of the battery. When charging only the battery core, the amount of change in the cumulative charge / discharge capacity = the amount of change in the cumulative charge capacity. When discharging only to the battery core, the amount of change in the cumulative charge / discharge capacity = the amount of change in the cumulative discharge capacity. There are discharge and reverse charge during actual driving, and the amount of change in the cumulative charge / discharge capacity = the change in the actual power amount of the battery = the amount of increase in the cumulative discharge capacity-the amount of increase in the cumulative charge capacity.

When the charging current of the battery core is equal to or greater than the sixth threshold value, the voltage parameter may be the open circuit voltage OCV of the battery core. The detected voltage of the battery core may be OCV, or the detected voltage of the battery core may be input to a preset battery model and the OCV may be estimated by the battery model. Here, the sixth threshold value indicates a low-speed charging rate reference value, and the charging current of the household electric device falls into the category of the low-speed charging rate as compared with the current at the time of charging by the charging gun of the vehicle.

If the charging current of the battery core is less than the sixth threshold, the voltage parameter may be the detected voltage Volt of the battery core. Since the battery tends to be in a stable state in the low-speed charge state, the SOH correction strategy of the embodiment of the present application can be executed by using the detected voltage of the battery core as it is in the low-speed charge state.

FIG. 2 is a schematic diagram of a dQ / dOCV-OCV relationship graph according to an embodiment of the present application. The dQ / dOCV-OCV relationship graph can be determined by the collected voltage parameter series and cumulative charge / discharge capacity series.

Referring to FIG. 2, for any one point in the dQ / dOCV-OCV relationship graph, the dOCV indicated by the point is the OCV indicated by the point after sorting the voltage parameter series OCVi and the OCV indicated by the previous point. The dQ indicated by the point is the difference between the cumulative charge / discharge capacity corresponding to the OCV indicated by the point and the cumulative charge / discharge capacity corresponding to the OCV indicated by the previous point.

Alternatively, for any point in the dQ / dOCV-OCV relationship graph, the abscissa of that point can be understood to be the average value of two adjacent OCVs after sorting the voltage parameter series OCVi. The ordinates of can be understood as the difference in the cumulative charge / discharge capacity corresponding to the two adjacent OCVs described above. Those skilled in the art can determine the dQ / dOCV-OCV relationship graph as needed, and are not limited herein.

In one example, in order to improve the accuracy of the SOH correction calculation, the amount of data is sufficient by increasing the number of voltage parameter data in the voltage parameter series OCVi in the voltage parameter series OCVi involved in the calculation to be larger than the first threshold value. It is necessary to guarantee that it is. On the other hand, by making the absolute value of the difference between two adjacent voltage parameter data in the voltage parameter series OCVi smaller than the second threshold value, the difference becomes too large and the graph jumps up, or the calculated dQ / dOCV- It avoids the problem that the peak value information of OCV is hidden.

In step 102, the effective peak point in the relationship graph is determined.

In step 103, the SOH reference value corresponding to the voltage parameter data at the effective peak point is determined based on the correspondence between the peak voltage parameter data and the SOH reference value preliminarily defined.

In step 104, the current SOH is corrected based on the SOH reference value.

FIG. 3 is a graph showing changes with aging of dQ / dOCV-OCV according to the embodiment of the present application.

FIG. 3 shows a dQ / dOCVOCV graph when the aging degree is SOH1 and a dQ / dOCVOCV graph when the aging degree is SOH2, and SOH1> SOH2.

As can be seen from FIG. 3, each graph contains a plurality of peak points, and those skilled in the art can select the data of the plurality of peak points as necessary to form Table 1. can.

Table 1 is an orientation relation table according to an embodiment of the present application, which changes with aging of the dQ / dOCV-OCV graph corresponding to FIG. Table 1 shows OCV (3.4V, 3.65V and 3.9V) corresponding to the three peak values in the dQ / dOCV-OCV graph when the reference value is SOH1 and when the reference value is SOH2. The OCV (3.38V, 3.55V, 3.88V) corresponding to the three peak values in the dQ / dOCV-OCV graph is shown.

Combining FIGS. 3 and 1 and comparing the two dQ / dOCV-OCV graphs for SOH1 and SOH2, the peak values move relatively when the aging state changes from SOH1 to SOH2 due to the characteristics of the battery core material. , P1 moves to P1', p2 moves to P2', and p3 moves to P3'. That is, the OCV corresponding to the peak point tends to decrease with the aging of the battery.

Only two sets of peak value relationships for different degrees of aging are shown in FIGS. 3 and 1. In addition, when carrying out concretely, a person skilled in the art can define in detail the relationship between the peak values of a plurality of sets of different aging degrees, and the number of available peak values for each set of aging degrees can be determined. It can be selected, but it is not limited here.

In concrete implementation, those skilled in the art will determine the OCV corresponding to the peak value dQ / dOCV in each aging state (SOH), and then correspond to the actual peak value dQ / dOCV of the battery core. By searching the table for OCV, the aging state of the battery core can be estimated in reverse.

As described above, in the embodiment of the present application, regarding the phenomenon that the OCV-related graph changes remarkably after the battery core ages, the change law of the OCV-related graph is quantified, and the peak voltage parameter data and the SOH standardization pre-defined are quantified. Since the correspondence with the value is shown, if it is necessary to correct the SOH for the problem that the SOH estimation is inaccurate due to the deviation of the OCV-SOC relationship graph after aging, the cumulative charge / discharge capacity change amount of the battery core Obtain a relational graph between the ratio of the voltage parameter to the corresponding voltage parameter change amount and the voltage parameter itself, determine the effective peak point in the relational graph, and then obtain the pre-defined peak voltage parameter data and the SOH reference value. Since the current SOH can be corrected based on the SOH standard value only by determining the SOH standard value corresponding to the voltage parameter data at the effective peak point based on the correspondence between the two, the estimation accuracy of the SOH can be improved. Can be improved.

FIG. 4 is a flowchart of the SOH correction method according to the second embodiment of the present application, and the difference from FIG. 1 is that step 103 in FIG. 1 can be refined into steps 1031 and 1032 in FIG. , Is a diagram for explaining a method of acquiring a reference value of a first type of SOH.

In step 1031, the only effective peak point is determined from all the peak points of the relational graph.

In step 1032, the SOH control value corresponding to the voltage parameter data at the only effective peak point is determined based on the correspondence between the peak voltage parameter data pre-defined and the SOH control value.

That is, only one peak point is used in the calculation of the SOH control value, and the SOH control value corresponding to the OCV at the only effective peak point can be determined by searching from Table 1.

Specifically, step 1031 may be executed in two stages. First, a peak point satisfying the first predetermined condition is screened from the dQ / dOCV-OCV relationship graph, and then, among the peak points, the peak point at which the corresponding dQ / dOCV is maximized is determined as the only effective peak point. do.

The number of peak points satisfying the first predetermined condition is, for example, p1, p2. .. .. There may be more than one, such as pN. A total of two peak points p1 and p2 were screened, the voltage parameters corresponding to p1 and dQ / dOCV were 3.6V and 100, respectively, and the voltage parameters corresponding to p2 and dQ / dOCV were 3.55V and 250, respectively. In some cases, the p2 point is the only effective peak point.

The first predetermined condition is that the ratio of the cumulative charge / discharge capacity change amount corresponding to the peak point and the voltage parameter change amount exceeds the seventh threshold value, and the voltage parameter data corresponding to the peak point is set in advance. It is within the searchable range [OCVmin, OCVmax].

Here, the searchable range of the preset voltage parameter is determined by the correspondence between the preset peak voltage parameter data and the SOH reference value. For example, for the peak in Table 1 where the change with aging is most remarkable, the OCV when the SOH standard value corresponding to the peak is 100% and the SOH standard value corresponding to the peak are 70% (or). Of the OCV in the case of other preset SOH lower limit), the larger value can be OCVmax and the smaller value can be OCVmin.

According to Table 1, the OCVs corresponding to the three peak values of SOH1 (100%) are 3.4V, 3.65V, 3.9V, respectively, and correspond to the three peak values of SOH2 (70%). The OCVs are 3.38V, 3.55V, 3.88V, respectively, and the most remarkable change with aging is the peak of 3.65V (100% SOH), and all the changes with aging. Of the peaks of, only the peak corresponding to 3.65 V at 100% SOH is selected and used as a basis for determining the subsequent aging degree, and at this time, the corresponding peak within the entire life cycle corresponds. The OCV range is [3.55V, 3.65V].

The above example is only one method of a preset voltage parameter searchable range, and a person skilled in the art can determine an appropriate voltage parameter searchable range as needed, and the present invention is not limited thereto. ..

FIG. 5 is a diagram showing a flowchart of the SOH correction method according to the third embodiment of the present application, and the difference from FIG. 1 is that step 103 in FIG. 1 can be refined into steps 1033 and 1035 in FIG. It is a point and is a figure for demonstrating the acquisition method of the 2nd kind SOH reference value.

In step 1033, the top N peak points having the maximum peak value are selected as N effective peak points from all the peak points of the relational graph.

In step 1034, one difference vector is acquired for each SOH reference value and the voltage parameter data corresponding to the N effective peak points in the correspondence relationship between the peak voltage parameter data defined in advance and the SOH reference value. ..

Here, the difference vector is the difference between the first vector and the second vector, the first vector shows N peak voltage parameter data corresponding to the SOH reference value, and the second vector is N. The voltage parameter data corresponding to each effective peak point is shown.

In step 1035, among the difference vectors of a plurality of SOH standard values in the correspondence relationship between the peak voltage parameter data preliminarily defined and the SOH standard values, N valid SOH control values corresponding to the difference vectors having the smallest variance. The SOH reference value corresponding to the voltage parameter data at the peak point is used.

Hereinafter, the technical proposal of FIG. 5 will be illustrated.

Referring to Table 1, the OCVs corresponding to the three peak values in SOH1 form the first vector (OCVp1, OCVp2, OCVp3) and all the sorted peak value series di (di = dQi / dOCVi). The top three peak values having the largest values are screened offline, a second vector (OCVk1, OCVk2, OCVk3) is formed by the OCV corresponding to the top three peak values, and the first vector to the second one. Let the difference obtained by subtracting the vector be the difference vector, and let the variance of the difference vector be var.

The variance series variance is obtained from each SOHi in Table 1, and the SOH reference value corresponding to the case where the variance is the minimum is the SOHi value that best matches, and then the output and stored SOH are obtained based on the estimated SOHi value. Update.

Of the above two methods for acquiring the SOH reference value, the advantage of the first method is that the calculation amount is small because only one peak point is selected and judged, and the advantage of the second method is. Since it can be judged from multiple peaks, it is more robust to one-point error. Specifically, those skilled in the art can select the SOH standard value acquisition method as necessary, and the present invention is not limited thereto.

According to the embodiments of the present application, the dQ / dOCV-OCV relationship graph may be determined by the collected voltage parameter sequence (eg OCVi or Vi) and the cumulative charge / discharge capacity sequence Capi. Hereinafter, the acquisition method of each series will be described in detail based on different work situations.

The first type of work situation is the work situation of static charging, and in the work situation, the cumulative charge / discharge capacity in the charging process of the battery core is calculated until the charging of the battery core is completed or the charging is stopped. If the difference between the current cumulative charge capacity and the previous cumulative charge capacity reaches the third threshold, control the battery core to stop charging or reduce the charge current to the fourth threshold, and the second. After the predetermined time of 1 is maintained, charging of the battery core is restarted, and the voltage parameter series OCVi and the cumulative charge / discharge capacity series Capi are recorded once.

The second type of work situation is a continuous charging work state, in which the battery core is controlled and charging is continued until the charging of the battery core is completed or the charging is stopped. The voltage parameter series OCVi and the cumulative charge / discharge capacity series Capi are recorded once for each predetermined period.

The third type of work status is the work status of vehicle operation or the work status of discharge, and in the work status, until the difference between the current cumulative discharge capacity and the previous cumulative discharge capacity becomes less than the fifth threshold value. , The voltage parameter series OCVi and cumulative charge / discharge capacity sequence Capi are recorded once each time the battery core satisfies one quasi-SOC searchable state in the discharge process, which is the current cumulative discharge capacity and the previous cumulative total. This is because when the difference from the discharge capacity is large, the calculated peak value information of dQ / dOCV-OCV is obscured.

Here, the quasi-SOC searchable state includes, but is not limited to, one of the following conditions may be satisfied.

The standing time of the vehicle to which the electric core belongs reaches the first time.

The rest time of the vehicle to which the electric core belongs reaches the second time.

The time when the vehicle to which the electric core belongs is in the small current continuous discharge state reaches the third time.

Alternatively, the polarization voltage of the current voltage of the battery core is 0.

In this work situation, SOH can be estimated in the process of charging and discharging during operation of the vehicle, it is not necessary to fully discharge the battery core at a specific magnification, and it is necessary to set a specific charging / discharging work situation in advance. do not have. Further, the SOH is calculated from the ratio of the discharge capacity and the nominal capacity when the battery discharge ratio and the temperature in the prior art are required to be in a specific state, for example, when the battery is fully charged and then discharged to the off voltage at a constant ratio. It has great operability for what is needed.

The fourth type of work situation is a low-speed charge work situation, and since the low-speed charge current is small in the work situation, it is necessary to calculate the OCV or control the charge current to acquire the OCV. Instead, the dQ / dVolt-V graph being charged may be calculated directly based on the charge graph, i.e., based on the Vi series.

In one selectable embodiment, the SOC initial value (SOCcharg0) at the start of charging may exceed the search range in the table, so that the SOH correction method is a voltage corresponding to the cumulative charge / discharge capacity change amount of the battery core. Before the step (step 101) of obtaining the relationship graph between the ratio to the parameter change amount and the voltage parameter itself, the SOC initial value at the start of charging of the battery core is less than the maximum searchable SOC initial value. Includes steps to determine.

Hereinafter, in order to facilitate understanding by those skilled in the art, the SOH correction method according to the embodiment of the present application will be illustrated in detail.

FIG. 6 is a flowchart of the SOH correction method according to the fourth embodiment of the present application. As shown in FIG. 6, the SOH correction method includes steps 601 to 612.

In step 601, it is determined whether or not the battery core is being charged (for example, being charged by the charging gun), if so, step 602 is executed, and if not, step 601 is returned.

In step 602, the SOC value (SOCcharg0) at the start of charging is stored.

In step 603, it is determined whether or not SOCcharg0 is less than the preset maximum searchable SOC initial value, and if so, step 604 is executed, and if not, the flow is terminated.

In step 604, charging is stopped or the charging current is lowered to the designated threshold value I_Rest, and control is performed so that T_Rest continues for the designated time.

In step 605, the current voltage series Volti is stored and recorded, the current SOC series SOCi is stored and recorded, the current cumulative charge capacity series Capi is stored and recorded, and charging is restarted.

In step 606, it is determined whether or not the battery is fully charged or whether or not the battery is fully charged. If not, step 607 is executed, and if not, step 608 is executed.

In step 607, it is determined whether or not the difference between the current cumulative charge capacity and the previous cumulative charge capacity exceeds the threshold value δCap1, and if so, step 604 is executed to proceed to the next static control. If not, the process returns to step 605 to continue charging.

In step 608, the stored voltage series Volti is set to OCV series at the time of charging: OCV1, OCV2, ....

In step 609, the dQ / dOCV series: d1, d2, ... Are calculated.

In step 610, the only effective peak point P is screened from all the peak points satisfying the conditions in the dQ / dOCV-OCV graph.

In step 611, the peak value table of the dQ / dOCV-OCV graph of the battery core is searched to determine the SOHi corresponding to the peak value p.

In step 612, the current SOH is updated based on the estimated SOHi.

FIG. 7 is a flowchart of the SOH correction method according to the fifth embodiment of the present application. As shown in FIG. 7, the SOH correction method includes steps 701 to 709.

In step 701, it is determined whether or not the battery core is in the quasi-OCV searchable state (for example, discharging), if so, step 702 is executed, and if not, the process returns to step 701.

In step 702, the current voltage series Volti is stored and recorded, the current SOC series SOCi is stored and recorded, and the current cumulative charge / discharge capacity series Capi is stored and recorded.

In step 703, it is determined whether or not the difference between the current cumulative charge / discharge capacity and the previous cumulative charge / discharge capacity is less than δCap2, if so, step 704 is executed, and if not, the process returns to step 702. ..

Here, the reason why the difference between the two adjacent cumulative charge / discharge capacities is required to be less than the threshold value δCap2 is that if the difference between the two adjacent cumulative charge / discharge capacities is too large, dQ / dOCV is calculated. This is because the peak value information is obscured at that time.

In step 704, the stored voltage series Volti is set to OCV series: OCV1, OCV2, ....

In step 705, the dQ / dOCV series: d1, d2, ... Are calculated.

In step 706, it is determined whether or not the OCV sequence satisfies the preset sequence request, and if so, step 707 is executed, and if not, step 701 is executed.

In step 707, the maximum N peak values in the dQ / dOCV-OCV graph are calculated, and the top N peak values sorted by the magnitude of the corresponding OCV values are P1, P2, ... PN. ..

In step 708, the peak value table of the dQ / dOCV-OCV graph of the battery core is searched to determine the SOHi that best matches the peak values P1, P2, ... PN.

In step 709, the current SOH is updated based on the estimated SOHi.

FIG. 8 is a flowchart of the SOH correction method according to the sixth embodiment of the present application. As shown in FIG. 8, the SOH correction method includes steps 801 to 811.

In step 801 it is determined whether or not charging of the battery core has started, if so, step 802 is executed, and if not, the process returns to step 801.

In step 802, the SOC value (SOCcharg0) at the start of charging is stored.

In step 803, it is determined whether or not SOCcharg0 is less than the preset maximum searchable SOC initial value, and if so, step 804 is executed, and if not, the flow is terminated.

In step 804, the current voltage series Volti is stored and recorded, the current SOC series SOCi is stored and recorded, and the current cumulative charge capacity series Capi is stored and recorded.

In step 805, it is determined whether or not the battery is fully charged or stopped, and if not, step 806 is executed, and if so, step 807 is executed.

In step 806, it is determined whether or not the current charging time has reached a preset time, and if so, the process returns to step 805, and if not, the process returns to step 806.

In step 807, the OCV series OCV1, OCV2, ... During charging are estimated based on the voltage series Volti based on the battery model.

In step 808, the dQ / dOCV series: d1, d2, ... Are calculated.

In step 809, the only effective peak point P is screened from all the peak points satisfying the conditions in the dQ / dOCV-OCV graph.

In step 810, the peak value table of the dQ / dOCV-OCV graph of the battery core is searched to determine the SOHi corresponding to the peak value p.

In step 811 the current SOH is updated based on the estimated SOHi.

FIG. 9 is a flowchart of the SOH correction method according to the seventh embodiment of the present application. As shown in FIG. 9, the SOH correction method includes steps 901 to 910.

In step 901, it is determined whether or not the battery core has started low-speed charging, if so, step 902 is executed, and if not, the process returns to step 901.

In step 902, the SOC value (SOCcharg0) at the start of charging is stored.

In step 903, it is determined whether or not SOCcharg0 is less than the preset maximum searchable SOC initial value, and if so, step 904 is executed, and if not, the flow is terminated.

In step 904, the current voltage series Volti is stored and recorded, the current SOC series SOCi is stored and recorded, and the current cumulative charge capacity series Capi is stored and recorded.

In step 905, it is determined whether or not the battery is fully charged or whether or not the battery is fully charged. If not, step 906 is executed, and if so, step 907 is executed.

In step 906, it is determined whether or not the current charging time has reached a preset time, and if so, the process returns to step 905, and if not, the process returns to step 906.

In step 907, the dQ / dVolt series: d1, d2, ... Is calculated.

In step 908, the only effective peak point is screened from all the peak points satisfying the conditions in the dQ / dOCV-OCV graph.

In step 909, the peak value table of the dQ / dVolt-Volt graph of the battery core is searched to determine the SOHi corresponding to the peak value p.

In step 910, the current SOH is updated based on the estimated SOHi.

FIG. 10 is a block diagram of the SOH correction device according to the embodiment of the present application. As shown in FIG. 10, the SOH correction device includes a relationship graph acquisition module 1001, an effective peak point determination module 1002, an SOH reference value determination module 1003, and a SOH correction module 1004.

Here, the relationship graph acquisition module 1001 is used to acquire a relationship graph between the ratio of the cumulative charge / discharge capacity change amount of the battery core to the corresponding voltage parameter change amount and the voltage parameter itself.

The effective peak point determination module 1002 is used to determine the effective peak point in the relational graph.

The SOH standardization value determination module 1003 is used to determine the SOH standardization value corresponding to the voltage parameter data at the effective peak point based on the correspondence between the peak voltage parameter data preliminarily localized and the SOH standardization value.

The SOH correction module 1004 is used to correct the current SOH based on the SOH reference value.

The embodiments of the present application further provide a battery management system including the above-mentioned SOH correction device.

The embodiments of the present application further provide a computer-readable storage medium in which the program is stored, and the SOH correction method described above is realized when the program is executed by the processor.

Although the present invention has been described above with reference to preferred embodiments, various modifications can be made without departing from the scope of the present invention, and a part thereof can be replaced with an equivalent product. In particular, the technical features described in each embodiment can be combined in any way as long as there is no structural contradiction. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions within the scope of the claims.

Claims (13)

The step of acquiring the relationship graph between the ratio of the cumulative charge / discharge capacity change amount of the battery core to the corresponding voltage parameter change amount and the voltage parameter itself,
The step of determining the effective peak point in the relationship graph and
A step of determining the SOH control value corresponding to the voltage parameter data at the effective peak point based on the correspondence between the peak voltage parameter data and the SOH control value pre-defined.
A step of correcting the current SOH based on the SOH reference value, and
SOH correction method including. The relationship graph is determined by the collected voltage parameter series and cumulative charge / discharge capacity series.
For any one point in the relationship graph
The voltage parameter change amount indicated by the point is the difference between two adjacent voltage parameter data corresponding to the voltage parameter data indicated by the point after sorting the voltage parameter series.
The cumulative charge / discharge capacity change amount indicated by the point is the difference between the two cumulative charge / discharge capacities corresponding to the two adjacent voltage parameter data corresponding to the point after the sort in the cumulative charge / discharge capacity series. ,
The SOH correction method according to claim 1. The number of voltage parameter data in the voltage parameter series exceeds the first threshold and / or
The absolute value of the difference between two adjacent voltage parameter data in the voltage parameter series is less than the second threshold.
The SOH correction method according to claim 2. The relationship graph is determined by the collected voltage parameter series and cumulative charge / discharge capacity series.
The SOH correction method is
Until the charging of the battery core is completed or the charging is stopped, the cumulative charge / discharge capacity in the charging process of the battery core is recorded, and the difference between the current cumulative charge capacity and the previous cumulative charge capacity is the third. When the threshold is reached, the battery core is controlled to stop charging or the charging current is lowered to the fourth threshold, and after the first predetermined time is maintained, charging to the battery core is restarted and the voltage is reached. A step to record the parameter series and the cumulative charge / discharge capacity series once, or
Until the charging of the battery core is completed or the charging is stopped, the battery core is controlled to continue charging, and the voltage parameter series and the cumulative charge / discharge capacity series are performed once every second predetermined time. Steps to record or
Until the difference between the current cumulative discharge capacity and the previous cumulative discharge capacity becomes less than the fifth threshold value, each time the battery core satisfies one quasi-SOC searchable state in the discharge process, the voltage parameter series and the said Step to record the cumulative charge / discharge capacity series once,
Including
In the quasi-SOC searchable state, whether the stationary time of the vehicle to which the battery core belongs reaches the first time, the pause time of the vehicle to which the battery core belongs reaches the second time, or the battery core belongs to. The time during which the vehicle is in the low current continuous discharge state reaches a third time, or the polarization voltage of the current voltage of the battery core is zero.
The SOH correction method according to claim 1. Before the step of acquiring the relationship graph between the ratio of the cumulative charge / discharge capacity change amount of the battery core to the corresponding voltage parameter change amount and the voltage parameter itself, further
The step including determining that the SOC initial value at the start of charging of the battery core is less than the preset maximum searchable SOC initial value.
The SOH correction method according to claim 1. When the charging current of the battery core is equal to or greater than the sixth threshold value, the voltage parameter is the open circuit voltage OCV, which is determined by the detection voltage of the battery core.
When the charging current of the battery core is less than the sixth threshold value, the voltage parameter is the detected voltage of the battery core.
The SOH correction method according to claim 1. The step of determining the SOH control value corresponding to the voltage parameter data at the effective peak point based on the correspondence between the peak voltage parameter data and the SOH control value set in advance is
The step of determining the only effective peak point from all the peak points of the relationship graph,
A step of determining the SOH reference value corresponding to the voltage parameter data at the only effective peak point based on the correspondence between the pre-defined peak voltage parameter data and the SOH reference value.
The SOH correction method according to claim 1. The step of determining the only effective peak point from all the peak points in the relationship graph is
A step of screening a peak point satisfying the first predetermined condition from the relationship graph, and
The step of determining the peak point at which the corresponding cumulative charge / discharge capacity change amount at the peak point is maximum is defined as the only effective peak point.
Including
The first predetermined condition is that the ratio of the cumulative charge / discharge capacity change amount corresponding to the peak point and the voltage parameter change amount exceeds the seventh threshold value, and the voltage parameter data corresponding to the peak point is set in advance. The voltage parameter is within the searchable range,
The SOH correction method according to claim 7. The preset voltage parameter searchable range is determined by the correspondence between the preset peak voltage parameter data and the SOH reference value.
The SOH correction method according to claim 8. The step of determining the SOH control value corresponding to the voltage parameter data at the effective peak point based on the correspondence between the peak voltage parameter data and the SOH control value set in advance is
A step of selecting the top N peak points having the largest peak value from all the peak points of the relationship graph as N effective peak points, and
The first vector and the second vector with respect to each SOH reference value in the correspondence relationship between the pre-defined peak voltage parameter data and the SOH reference value, and the voltage parameter data corresponding to the N effective peak points. The difference vector, which is the difference from the above, is acquired, the first vector shows N peak voltage parameter data corresponding to the SOH reference value, and the second vector is the N effective peak points. Steps showing the corresponding voltage parameter data and
The SOH control value corresponding to the difference vector having the smallest variance among the difference vectors of a plurality of SOH control values in the correspondence relationship between the pre-defined peak voltage parameter data and the SOH control value is the voltage at N effective peak points. Steps to determine as the SOH reference value corresponding to the parameter data,
The SOH correction method according to claim 1. A relationship graph acquisition module that acquires a relationship graph between the ratio of the cumulative charge / discharge capacity change amount of the battery core to the corresponding voltage parameter change amount and the voltage parameter itself.
An effective peak point determination module that determines the effective peak point in the relationship graph,
An SOH standardization value determination module that determines the SOH standardization value corresponding to the voltage parameter data at the effective peak point based on the correspondence between the peak voltage parameter data and the SOH standardization value preliminarily localized.
An SOH correction module that corrects the current SOH based on the SOH reference value, and
SOH compensator, including. A battery management system including the SOH correction device according to claim 11. A computer-readable storage medium in which a program is stored,
A computer-readable storage medium in which the SOH correction method according to any one of claims 1 to 10 is realized when the program is executed by a processor.

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